Why in the News?

A recent study has revealed that the mean PM2.5 concentration in Assam is higher than the national average, raising concerns about public health and monitoring gaps.

Key Findings on Air Quality Monitoring

• The mean PM2.5 concentration (2000–2022) in Assam was 49.5 µg/m³, above the NAAQS annual limit of 40 µg/m³.

• A west-to-east gradient is seen: western and southwestern districts record >60 µg/m³, while northeastern districts remain below 40 µg/m³.

• Contributing factors include industrial belts, cross-border pollution, vehicular emissions, and meteorological conditions.

• CPCB guidelines mandate at least 1 PM2.5 station per 10 lakh people, with a minimum of 1 per district.

• Based on this, Assam needs 32 monitors (population-based) or 55 monitors (district-based).

• Nagaon requires 3 monitors, while smaller districts like Dima Hasao and Chirang require 1 each.

• Assam currently has 9 CAAQMS, with 4 in Guwahati, and 63 manual AAQM stations covering only 20 districts.

• Proposals for additional stations are still pending CPCB approval.

Reasons Behind High Air Pollution in Assam

1. Urban and Industrial Emissions

• Guwahati, the fastest-growing urban hub, suffers from vehicular emissions, construction dust, and industrial activity.

• Industrial hotspots include Digboi refinery, Bokajan cement industry, and the Guwahati–Byrnihat industrial corridor.

2. Vehicular Growth and Congestion

• Rapid increase in vehicles in urban centers has led to high NO₂ and PM emissions.

• Dependence on private vehicles and inadequate public transport aggravates the problem.

• Diesel-run commercial vehicles are a major source of black carbon.

3. Cross-Border Pollution

• Western and southwestern districts face inflows of pollutants from Bangladesh and West Bengal, worsening PM levels.

4. Seasonal and Natural Sources

• Forest fires in Assam and neighboring states release large amounts of PM2.5.

• Crop residue burning adds to seasonal peaks, particularly in western districts.

• Temperature inversion in winters traps pollutants close to the ground.

• High humidity aids smog formation.

5. Construction and Urbanization

• Dust from construction, roadworks, and urban sprawl contributes to PM pollution.

• Informal waste burning in expanding towns adds to localized air quality issues.

6. Agricultural Practices

• Crop residue burning, though less severe than in Punjab–Haryana, remains locally significant.

7. Biomass Burning

• Domestic use of firewood, cow dung, and crop residues in rural households adds to indoor and ambient air pollution.

8. Weak Monitoring and Enforcement

• Assam has only 9 CAAQMS for 35 districts, leaving most areas unmonitored.

• Emission norms for industries and vehicles are poorly enforced, allowing unchecked pollution.

Health Impacts

• Long-term exposure to PM2.5 is linked with asthma, COPD, cardiovascular diseases, and premature mortality.

• Children and elderly are the most vulnerable groups.

• Assam’s healthcare system faces a dual burden of infectious diseases and rising NCDs due to pollution.

Policy and Governance Issues

• Assam is a “non-attainment State” under the NCAP, with targets of 20–30% reduction in PM2.5 and PM10 by 2027 (over 2017 baseline).

• Weak enforcement, fragmented responsibilities, and limited funding hinder effective air quality management.

Contributors to Air Pollution (In Brief)

• Industrial emissions: Digboi refinery, Bokajan cement, Byrnihat corridor.

• Vehicular emissions: Rapid motorization, diesel vehicles, traffic congestion.

• Construction dust and urban expansion

• Cross-border pollution: Inflow from Bangladesh and West Bengal.

• Agricultural residue burning in western districts.

• Forest fires and biomass burning in rural households.

• Meteorological factors: Inversions, humidity, valley effects.

Way Forward

• Strengthen monitoring: Ensure at least one CAAQMS per district and expand towards the 55 monitors target.

• Phased expansion: Prioritize hotspots like Digboi, Bokajan, and Guwahati–Byrnihat corridor.

• Low-cost sensors: Deploy in rural and forest-fringe areas for community-level tracking.

• Integrated system: Create a state-level dashboard combining ground data, satellite inputs, meteorology, and fire-detection tools.

• Capacity building: Improve financial and technical capabilities of the Pollution Control Board of Assam (PCBA).

• Strict enforcement under NCAP: Regulate industrial emissions, upgrade vehicular standards, and implement pollution-control measures to achieve the 2027 reduction targets.

Mains-Question

Q. Despite being a biodiversity-rich state, Assam faces serious challenges due to rising air pollution, particularly in urban and industrial belts. Discuss the major causes of air pollution in Assam, the gaps in monitoring infrastructure, and suggest measures to ensure sustainable air quality management in the state. (250 words/15 marks)